Blisters and Chafing From Running: Prevent and Treat Them

Most running blisters are friction blisters, and most heal on their own within a week or two. The fix is mostly about stopping the rubbing: shoes that fit, socks that keep your feet dry, and clothing that does not soak up sweat. This page pulls together what the NHS, MedlinePlus (run by the U.S. National Library of Medicine) and the American Academy of Dermatology (AAD) say, as of October 2026.

1. Why running causes blisters

A blister is a small pocket of fluid under a layer of skin. MedlinePlus says blisters often form when there is friction, meaning rubbing or pressure on one spot, and gives the example of shoes that do not fit quite right and keep rubbing part of the foot. The NHS adds that blisters develop to protect damaged skin and help it heal.

Running repeats the same motion for a long time, so a small rub can build up in one spot. The AAD notes that cotton soaks up sweat and moisture, which can lead to friction and chafing, and that the same logic applies anywhere skin rubs skin or clothing, such as the inner thighs.

2. How to prevent them

The three sources agree on the basics:

• Check the fit. The AAD says shoes should not be too tight or too loose. The NHS suggests wearing new shoes for short periods until they are comfortable.
• Choose the right socks. The AAD recommends nylon or moisture-wicking socks, and says that if one pair does not help, two pairs may protect the skin. MedlinePlus suggests acrylic or nylon socks that keep moisture away from the feet. The NHS suggests changing socks often if your feet sweat.
• Wear loose, moisture-wicking clothing. The AAD says to avoid cotton for exercise.
• Pad known problem spots. For areas such as the feet or thighs, the AAD suggests adhesive moleskin or other soft bandages applied securely, and powder or petroleum jelly where skin rubs together or against clothing.
• Stop when it hurts. The AAD says to stop the activity immediately if you feel pain or discomfort, or if the skin turns red. Otherwise you may get a blister.

Hands can blister too. Both the NHS and MedlinePlus mention gloves when equipment rubs your hands.

3. What to do if you already have a blister

The sources give a consistent set of steps for an intact blister:

1. Leave it alone if you can. The skin over a blister helps keep infection out, according to MedlinePlus. The NHS says not to burst a blister yourself.
2. Cover it loosely. The AAD describes a bandage with the sides brought in so the middle is slightly raised. For pressure areas such as the sole of the foot, it suggests a donut-shaped pad with a hole in the middle placed around the blister, then covered with a bandage.
3. Remove the cause. MedlinePlus says to make sure there is no more rubbing on the blister. The NHS says not to wear the shoes or equipment that caused it until it heals.
4. Ask a pharmacist about dressings. The NHS says a hydrocolloid dressing (a moist dressing) can protect the blister, help reduce pain and speed up healing.

3.1. If it is huge, painful or has burst

MedlinePlus says you normally do not want to drain a blister because of infection risk, but if it is large, painful or about to pop, you can drain the fluid. The AAD describes sterilizing a small needle with rubbing alcohol and piercing one edge so the fluid can drain, then washing with soap and water and applying petroleum jelly. For a blister that has already burst, the NHS says to let the fluid drain, wash your hands before touching it, and cover it with a plaster or dressing.

Across the AAD and NHS, one point is the same: do not remove the skin over the blister. The AAD says the "roof" protects the raw skin underneath, and the NHS says not to peel the skin off a burst blister or pick at its edges.

4. How long it takes, and when to get help

The NHS says blisters often heal on their own within a week. The AAD says most heal in one to two weeks and recommends not resuming the activity that caused the blister until it has healed.

Contact a health professional if you see signs of infection. MedlinePlus lists pus, or a blister area that is red, swollen, warm or very painful, and also fever. The NHS adds that a blister that is very painful or keeps coming back, several blisters with no obvious reason, and blisters caused by a burn, sunburn or allergic reaction are reasons to call NHS 111. MedlinePlus also lists health problems such as circulation problems or diabetes as a reason to contact a provider.

5. Key takeaways

• Friction is the main cause. Reduce rubbing and the blister usually does not form.
• Well-fitting shoes, moisture-wicking socks and non-cotton clothing are the common advice from all three sources.
• Cover an intact blister loosely and keep the roof of the skin in place.
• Draining is a last resort for large, painful blisters, and the AAD gives the sterile steps.
• Stop running on a blister until it heals, and get medical advice for infection signs, fever, diabetes or circulation problems.